```css
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: Arial, sans-serif;
  line-height: 1.6;
  color: #333;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* 头部 */
.header {
  background: #fff;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  padding: 20px 0;
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo img {
  height: 60px;
}

.search-bar {
  display: flex;
}

.search-bar input {
  padding: 8px;
  border: 1px solid #ccc;
  border-radius: 4px 0 0 4px;
  width: 200px;
}

.search-bar button {
  padding: 8px 16px;
  background: #007bff;
  color: #fff;
  border: none;
  border-radius: 0 4px 4px 0;
  cursor: pointer;
}

.search-bar button:hover {
  background: #0056b3;
}

/* 导航栏 */
.nav {
  background: #004085;
}

.nav ul {
  display: flex;
  list-style: none;
}

.nav li {
  flex: 1;
}

.nav a {
  display: block;
  padding: 15px;
  color: #fff;
  text-align: center;
  text-decoration: none;
}

.nav a:hover {
  background: #0056b3;
}

/* 图片展示区 */
.banner {
  width: 100%;
  height: 400px;
  overflow: hidden;
}

.banner img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* 新闻版块 */
.news {
  padding: 40px 0;
  background: #f8f9fa;
}

.news h2 {
  text-align: center;
  margin-bottom: 20px;
  font-size: 24px;
}

.news-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.news-item {
  background: #fff;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.news-item img {
  width: 100%;
  height: 150px;
  object-fit: cover;
}

.news-item h3 {
  padding: 10px;
  font-size: 18px;
}

.news-item p {
  padding: 0 10px 10px;
  font-size: 14px;
  color: #666;
}

/* 公告版块 */
.notices {
  padding: 40px 0;
}

.notices h2 {
  text-align: center;
  margin-bottom: 20px;
  font-size: 24px;
}

.notice-list {
  list-style: none;
}

.notice-list li {
  display: flex;
  justify-content: space-between;
  padding: 10px;
  border-bottom: 1px solid #eee;
}

.notice-list a {
  color: #007bff;
  text-decoration: none;
}

.notice-list a:hover {
  text-decoration: underline;
}

.notice-list span {
  color: #666;
  font-size: 14px;
}

/* 主内容区 */
.main-content {
  padding: 40px 0;
  background: #f8f9fa;
}

.content-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.content-item {
  background: #fff;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.content-item img {
  width: 100%;
  height: 200px;
  object-fit: cover;
}

.content-item h2 {
  padding: 10px;
  font-size: 20px;
}

.content-item p {
  padding: 0 10px 10px;
  font-size: 14px;
  color: #666;
}

.content-item .more {
  display: block;
  padding: 10px;
  text-align: center;
  color: #007bff;
  text-decoration: none;
}

.content-item .more:hover {
  background: #f1f1f1;
}

/* 专题网站版块 */
.special-sites {
  padding: 40px 0;
}

.special-sites h2 {
  text-align: center;
  margin-bottom: 20px;
  font-size: 24px;
}

.sites-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.site-item {
  display: block;
  background: #fff;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  text-align: center;
  text-decoration: none;
  color: #333;
}

.site-item img {
  width: 100%;
  height: 120px;
  object-fit: cover;
}

.site-item span {
  display: block;
  padding: 10px;
  font-size: 16px;
}

.site-item:hover {
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

/* 页脚 */
.footer {
  background: #333;
  color: #fff;
  padding: 20px 0;
  text-align: center;
}

.footer p {
  margin: 5px 0;
}

/* 响应式设计 */
@media (max-width: 768px) {
  .header .container {
    flex-direction: column;
    gap: 10px;
  }

  .search-bar input {
    width: 100%;
  }

  .nav ul {
    flex-direction: column;
  }

  .news-grid, .content-grid, .sites-grid {
    grid-template-columns: 1fr;
  }

  .banner {
    height: 200px;
  }
}
```